Mystery Plant

This is one of the most beloved of all eastern North American trees, and nearly everybody has heard of it. Funny thing is, a lot of people wouldn’t recognize its leaves or flowers.

It is a tall giant of mature American forests, with one of the straightest trunks there is. Historical specimens, now long gone, towered to nearly 200 feet. The bark is deeply gray and furrowed on mature trees. Young branches are smooth and green, eventually revealing chambered pith inside. The scratched twigs are very pleasantly fragrant, but rather bitter to the taste. The leaves, of course, are instantly recognizable. A long petiole is topped by a square-ish blade, this generally four-lobed, or “cornered.” The apex of the leaf is flattened, or even a bit indented. This leaf looks something like a tulip flower in two dimensions. The flowers, too, are somewhat like tulips, and usually produced high enough in the crown (on big trees) that they aren’t commonly viewed, unless blown down in a storm. Three greenish sepals are at the flower base. Nine (or so) green-yellow petals are present, too, each of these with a prominent orange blotch or crescent on the inner surface. Plenty of pointed stamens surround the base of a cone-like arrangement of overlapping pistils, and each of these pistils eventually produces a dry, single-seeded fruit. The fruits, fallen on the forest floor are often eaten by critters, but the survivors remain in the seed “bank” several years before sprouting.

This species is what’s called a forest “pioneer.” The seedlings are intolerant of shade, and so young plants are not encountered in forests of deep, closed canopies overhead. Rather, the young trees come up prolifically in open areas, usually caused naturally by large trees fallen in storms, forming light gaps. The young ones also come up readily after timbering operations, sometimes forming nearly pure stands. As these dense populations age, most of the trees die out, so that in a recovered, mature forest, large individuals of this species are usually scattered.

It grows naturally from New England to Lake Michigan, south to northern Florida and Louisiana. It makes a great street tree and grows rapidly, providing excellent summer shade, and seems to have few insect enemies. In its native range, it grows well at many elevations, and well into the lush slopes and higher terrain of the Appalachians. The national champion, which has a trunk diameter of 9 feet, is located in Bedford, Va., but there are plenty of close competitors. There is only one other species in the same genus, a very close relative, which, interestingly, is native to Eastern Asia.

The pressed plant image is from a collection made by Henry W. Ravenel, one of South Carolina’s most famous botanists. His specimen, from “rich woods” near his home in Berkeley County, South Carolina, was probably collected in the early 1850s. The specimen itself is in very good physical shape, and is an excellent example of an early herbarium specimen.

John Nelson is the curator of the Herbarium at the University of South Carolina, in the Department of Biological Sciences, Columbia, S.C. 29208. As a public service, the Herbarium offers free plant identifications. For more information, visit www.herbarium.org or call (803) 777-8196.

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